Help rough running 5.0

RPM289 · 06-26-2003

I have a 89 5.0 in a Crown Vic that runs rough all through the RPM range
I replaced the cap rotor pulgs and wires so far with no change. I do not know alot about the EFI engines so all help would be great.

Thanks,
Mike

mccoigk · 06-27-2003

Try this link:

http://www.allfordmustangs.com/Detailed/58.shtml

I took the advice here and things ran a little smoother for me. just my .02

RPM289 · 06-27-2003

Thanks for the link! I have done everything on there except the intake cleaning. I did remove the idle bypass valve and used a whole can of carb cleaner to clean it up. I did unplug the throttle position sensor and it helped a good bit but the check engine light came on then. The light is not on when it is plugged up so is it bad or just pointing to something else? I was told the EGR valve can cause this, is this true? And one last question. If I take it to a shop and have them plug it up and check the codes will it show anything if the chece engine light is not on? I can,t believe the light is not on as rough as it is running.

Thanks agian everyone.
Mike

vbrpete · 06-28-2003

Clean that intake!

Or better yet,replace it with one from an'87-up Mustang.The bigger throttle body and throat make a good difference on the Vic motor.The EGR CAN become plugged up,and if left open will definitely cause your problem.Also check the hard plastic lines leading to the EGR and TAB/TAD solenoids.If broken they will cut off the vacuum to the EGR AND provide a wicked vacuum leak.

If you REALLY want to help it out,throw in an H.O. cam and valve springs too.These changes pop it up to 200+ from your 150.You'll have to change the computer too,and most Vics can use the H.O. computer with only minor changes to the cruise control.

These changes,plus a set of 3.55s make the Vic a blast to drive,trust me.My old daily driver '88 eventually made it down to 14.96 @ 93.22 with only these changes and a "track diet".Blew some minds that night...

RPM289 · 06-28-2003

I did not know that this was a roller motor!! Those a good times for such a big car, but I don't think the mom-in-law is in to performance! LOL. I did notice yesterday that the fittinng between the exahust tubing and the valve behind the air pump was broken. I have heard you can plug it off with no problems. Or is that the source of my problem?

Thanks!
Mike

vbrpete · 06-29-2003

Go ahead and plug the valve,that isn't the source of the problem.Just run through the preceding list and keep your eyes open for any odd stuff like the pipe you found.

RPM289 · 06-29-2003

Quote:

Originally posted by vbrpete
Go ahead and plug the valve,that isn't the source of the problem.Just run through the preceding list and keep your eyes open for any odd stuff like the pipe you found.

Good news! I cleaned the intake at a cost of 2 cans of carb cleaner MAJOR Improvement!! I also reset the base idle after cleaning and it runs much better now. Thanks for all your help!!!!

vbrpete · 06-30-2003

I love it when a plan comes together......